This invention relates to a forming method and forming machine for chocolate and the like, such as fondant, nougat, creams, etc. With this premise, reference will be simply made hereinafter to chocolate.
As is known, conventional forming machines are used for the metered transfer of chocolate from a hopper containing it into forming plates or molds to form a desired product, such as chocolate bars, candies, stuffed candies, etc. Forming machines conventionally comprise in essence one or two hoppers containing stirring means and opening into a respective rotary valve chamber provided with throughgoing passages and being associated, on the one side, with a metering unit for metering out a desired amount of the product, and on the other side, with conduits in the forming machine which open into holes or channels of molding plates associated with the forming machine at the bottom thereof. The metering units comprise a cylinder-piston units which are provided laterally to said rotary valves, and during a rotation phase thereof, are communicated to a respective hopper compartment, and as the pistons are removed rearwardly, effect the suction of a given metered amount of chocolate into the respective cylinder, thereafter, with said rotary valves turned to a successive position, through the outward movement of the pistons, they determine the delivery of said chocolate through outlet conduits from the forming machine which lead into the holes or conduits in the cited forming plates.
A known construction of the forming machine and forming plates is disclosed, for example, in Italian Pat. No. 488,620 to this same Applicant.
Also known in the art is that chocolate is in a pre-crystallization state in forming machines, so that only very short processing times are available to prevent the onset of crystallization, which is to occur subsequently to forming. Thus, it is extremely important that the chocolate temperature be maintained as accurately as possible from the hopper to the forming plates or molds.
Prior forming machines have in practice several disadvantages and deficiencies of constructional, functional, and physic-structural characters as regards their action on the chocolate, the most important whereof are listed here below:
The utilization of cylinder-piston units, or reciprocating units, located on the outside, which increases considerably the machine space requirements.
The use of cylinder-piston units allows the utilization of forming machines having at most two hoppers, and accordingly, two sets of cylinder-piston units on the machine opposed sides. Thus, in the instance of chocolate candies including three or more ingredients or different qualities, it becomes necessary to arrange two successive forming machines in series, with attendant increased bulk and substantial investment cost.
With prior cylinder-piston units, the pistons, during their backward stroke, or chocolate loading stroke, come out of the cylinder casings and are, therefore, fully exposed to air and bacterial load of the environment.
The entire inner lateral surface of the cylinders forms a frictionsurface acting on the chocolate being displaced, which results in the same being crystallized, thereby a circumferential chocolate film is formed which tends to harden and seize the pistons. Upon the occurrence of each seizure, the machine must be stopped for cleaning. The net result is loss of production and increased labor attendance.
In the instance of sugar fondant, in order to avoid the crystallization of the sugar film on the pistons in their outward movement, it is common practice to accept the continuous loss of that sugar film, as well as continued wetting of the pistons with water, which obviously represents an economical disadvantage and waste of product.
At the end of each daily working shift the cylinder-piston unit must be accurately cleaned to ensure its reliable operation as the machine is started at the next shift. Such cleaning operations are time-consuming and must be performed with care, it involving disassembling the pistons, washing the pistons and cylinders, and perfectly drying them to eliminate all traces of moisture and minimize the environmental load on such parts. Moreover, application of a thin film of cocoa butter would be advisable.
In the cylinder-piston units, sealing is accomplished by means of gaskets, that is, parts which are liable to wear out.
In order to change the piston stroke length, that is to vary the amount of product being metered out, prior units require complex linkages formed by several parts articulated to one another. These are difficult to keep adjusted, especially evenly adjusted between units.
Owing to different manufacture tolerances of the individual parts, on the one side, and the stresses and unavoidable wear on the other side, different clearances appear at the various units, and accordingly, different amounts being metered out of the finished product. Since the product weights are assessed at tolerances of tenths of a gram, such clearances pose considerable difficulties owing to strict weight tolerance regulations being applied in the various countries.
Leaky gaskets result in the metered amounts of chocolate incorporating air bubbles, which are retained in the finished product, thus creating well known difficulties when this is to be ejected.
The volume output rate is low, because it depends, in addition to the product viscosity, also on a perfect seal at the gaskets and on the clearances present, in particular an improper seal causing the adduction of air and formation of air bubbles as above.
With conventional reciprocating units, metering is accompanied by "violent" actions on the chocolate. In fact, a loading step is first carried out by "sucking" the chocolate from the hopper through the rotary valve into the cylinder, and then a step of delivery of the same from the cylinder into the rotary valve. Of course, during the "suction" step a "stretching" action is applied on the chocolate being introduced into the cylinder, and during the following delivery step the chocolate undergoes a squeezing action. Thus, such actions are "violent" and as is known affect and deprive the product of its final shine, a feature much sought after.
Long travel distance paths are provided for the chocolate to reach the forming plates or molds from the hopper, which extend both upstream and downstream of the rotary valves. This involves the need for a complicated and expensive arrangement for keeping the several parts of the forming machine, located at some distance apart, at a desired temperature.
Notwithstanding the provision of agitators in the hoppers, conventional forming machines are unable to meter out materials which are highly viscous, such as marzipan.
To provide the required synchronization of the piston movement with that of the rotary valves, as well as of the movement of said rotary valves with the feeding means for the forming molds, highly expensive constructions and apparata are required. Further, prior synchronization arrangements disallow the desired simplicity and "elasticity" of adaptation in the event of the molds, or size thereof, being changed.
Owing to the axial motion of the metering units, the chocolate is metered out discontinuously at marhedly long intervals, because one stroke of the pistons must materially take place after another. At the end of the loading, more over, the pistons are exposed to ambient temperature, and are consequently liable to lose some heat.
In the case of forming molds being fed continuously it is is also necessary to reciprocate the forming machine. This involves considerable expenditures in construction, apparata, and energy.
With prior metering units, the loading, or metering and ejection, or delivery phases of the chocolate take place in an indipendent fashion and are neatly separated from one another.
To keep the product under stirring agitation agitators must be provided at the hoppers. Downstream of the hoppers, no agitation of the product will take place, therefore, which tends to cause the product to crowd together.